一、找到抽象化的对象
1.书类
经过分析，我们可以知道，书可以抽象成一个类型。它的属性包括：书名，作者，价格，书的类型等等...我们就先以这些为例。为了保持封装性，我们把这些属性都设置成private修饰的。
下面是书类的定义代码：
这段代码包括一些构造函数以及设置书的属性、重写String函数等。
public class Book { private String name; private String author; private int price; private String type; private boolean isBorrowed; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public int getPrice() { return price; } public void setPrice(int price) { this.price = price; } public String getType() { return type; } public void setType(String type) { this.type = type; } public boolean isBorrowed() { return isBorrowed; } public void setBorrowed(boolean borrowed) { isBorrowed = borrowed; } public Book(String name, String author, int price, String type) { this.name = name; this.author = author; this.price = price; this.type = type; } @Override public String toString() { return "Book{" + "name='" + name + '\'' + ", author='" + author + '\'' + ", price=" + price + ", type='" + type + '\'' + ((isBorrowed==true)?"已借出！":"未借出！") + '}'; } }
2.书架类
我们可以利用一个数组来存放这些书籍，并记录当前存放书籍的数量，为后续的增删查改做准备，同时初始化有三本书籍。
下面是代码：
public class BookList { private Book[] books; private int usedSize;//记录当前书架上实际存放的书的数量 public BookList(){ this.books=new Book[10]; this.books[0]=new Book("三国演义","罗贯中",18,"小说"); this.books[1]=new Book("西游记","吴承恩",28,"小说"); this.books[2]=new Book("红楼梦","曹雪芹",35,"小说"); this.usedSize=3; } //获取当前存放书籍数量 public int getUsedSize() { return usedSize; } //设置存放书籍数量 public void setUsedSize(int usedSize) { this.usedSize = usedSize; } //返回下标为pos的书籍 public Book getBook(int pos){ return books[pos]; } //设置下标为pos位置的书籍为book public void setBook(int pos,Book book){ books[pos]=book; } //返回书籍这个数组 public Book[] getBooks(){ return books; } }
二、管理员与普通用户登录
首先定义一个用户抽象类，再定义管理员与普通用户去继承抽象类并重写菜单方法。
下面是用户抽象类代码：
abstract public class User { protected String name; protected IOPeration[] ioPerations; public User(String name) { this.name = name; } public abstract int menu(); public void doOperation(int choice, BookList bookList){ ioPerations[choice].work(bookList); } }
管理员类代码：
public class AdiminUser extends User{ public AdiminUser(String name){ super(name); this.ioPerations=new IOPeration[]{ new ExitOperation(), new FindOperation(), new AddOperation(), new DelOperation(), new ShowOperation() }; } public int menu(){ System.out.println("********管理员*********"); System.out.println("1.查找图书"); System.out.println("2.新增图书"); System.out.println("3.删除图书"); System.out.println("4.显示图书"); System.out.println("0.退出系统"); System.out.println("*********************"); Scanner scanner=new Scanner(System.in); System.out.println("请输入你的选择:>"); int choice=scanner.nextInt(); return choice; } }
普通用户类代码：
public class NormalUser extends User{ public NormalUser(String name){ super(name); this.ioPerations=new IOPeration[]{ new ExitOperation(), new FindOperation(), new BorrowedOperation(), new ReturnOperation() }; } public int menu(){ System.out.println("*******普通用户*******"); System.out.println("1.查找图书"); System.out.println("2.借阅图书"); System.out.println("3.归还图书"); System.out.println("0.退出系统"); System.out.println("********************"); Scanner scanner=new Scanner(System.in); System.out.println("请输入你的选择:>"); int choice=scanner.nextInt(); return choice; } }
三、实现的功能
实现以下几个功能，可以定义一个接口，方便后续的相关操作。
public interface IOPeration { void work(BookList bookList); }
1.查找图书
public class FindOperation implements IOPeration{ @Override public void work(BookList bookList) { System.out.println("查找图书>:"); System.out.println("请输入要查找的书>:"); Scanner scanner=new Scanner(System.in); String name=scanner.nextLine(); //遍历这个数组 int currentSize=bookList.getUsedSize(); for (int i = 0; i < currentSize; i++) { Book book=bookList.getBook(i); if(book.getName().equals(name)){ System.out.println("该书信息如下>:"); System.out.println(book); return; } } System.out.println("无此书!!!"); } }
2.新增图书(管理员功能)
public class AddOperation implements IOPeration{ @Override public void work(BookList bookList) { System.out.println("新增图书>:"); int cunrrentSize=bookList.getUsedSize(); if (cunrrentSize==bookList.getBooks().length){ System.out.println("书架已满！"); return; } Scanner scanner=new Scanner(System.in); System.out.println("输入要新增书籍>:"); String name=scanner.nextLine(); //检查数组当中有没有这本书 for (int i = 0; i <cunrrentSize ; i++) { Book book1=bookList.getBook(i); if(book1.getName().equals(name)){ System.out.println("该书已存放，无需新增!!!"); return; } } System.out.println("输入书籍作者>:"); String author=scanner.nextLine(); System.out.println("输入书籍类型>:"); String type=scanner.nextLine(); System.out.println("输入书籍价格>:"); int price=scanner.nextInt(); Book book=new Book(name,author,price,type); bookList.setBook(cunrrentSize,book); bookList.setUsedSize(cunrrentSize+1); System.out.println("新增书籍成功!!!"); } }
3.删除图书(管理员功能)
public class AddOperation implements IOPeration{ @Override public void work(BookList bookList) { System.out.println("新增图书>:"); int cunrrentSize=bookList.getUsedSize(); if (cunrrentSize==bookList.getBooks().length){ System.out.println("书架已满！"); return; } Scanner scanner=new Scanner(System.in); System.out.println("输入要新增书籍>:"); String name=scanner.nextLine(); //检查数组当中有没有这本书 for (int i = 0; i <cunrrentSize ; i++) { Book book1=bookList.getBook(i); if(book1.getName().equals(name)){ System.out.println("该书已存放，无需新增!!!"); return; } } System.out.println("输入书籍作者>:"); String author=scanner.nextLine(); System.out.println("输入书籍类型>:"); String type=scanner.nextLine(); System.out.println("输入书籍价格>:"); int price=scanner.nextInt(); Book book=new Book(name,author,price,type); bookList.setBook(cunrrentSize,book); bookList.setUsedSize(cunrrentSize+1); System.out.println("新增书籍成功!!!"); } }
4.显示图书信息
public class ShowOperation implements IOPeration{ @Override public void work(BookList bookList) { System.out.println("显示图书>:"); int currentSize=bookList.getUsedSize(); for (int i = 0; i < currentSize; i++) { Book book=bookList.getBook(i); System.out.println(book); } } }
5.退出系统
public class ExitOperation implements IOPeration{ @Override public void work(BookList bookList) { System.out.println("退出系统>:"); System.exit(0); } }
6.借阅图书(普通用户功能)
public class BorrowedOperation implements IOPeration{ @Override public void work(BookList bookList) { System.out.println("借阅图书>:"); /** * 1.你要借阅哪本书？ * 2.你借阅的书存在吗？ * 借阅的方式是什么？ */ Scanner scanner=new Scanner(System.in); System.out.println("输入要借阅书籍>:"); String name=scanner.nextLine(); int currentSize=bookList.getUsedSize(); int i = 0; for (; i <currentSize ; i++) { Book book=bookList.getBook(i); if(book.getName().equals(name)){ book.setBorrowed(true); System.out.println("借阅成功!!!"); return; } } if(i==currentSize){ System.out.println("该书不存在，无法借阅!!!"); } } }
7.归还图书(普通用户功能)
public class ReturnOperation implements IOPeration{ @Override public void work(BookList bookList) { System.out.println("归还图书>:"); Scanner scanner=new Scanner(System.in); System.out.println("输入要归还书籍>:"); String name=scanner.nextLine(); int currentSize=bookList.getUsedSize(); int i = 0; for (; i <currentSize ; i++) { Book book=bookList.getBook(i); if(book.getName().equals(name)){ book.setBorrowed(false); System.out.println("归还成功!!!"); return; } } if(i==currentSize){ System.out.println("该书不存在，无需归还!!!"); } } }
四、main方法
public class Main { public static User login() { System.out.println("请输入你的姓名:>"); Scanner scanner = new Scanner(System.in); String name = scanner.nextLine(); System.out.println("请输入你的身份:> 1.管理员 2.普通用户"); int choice = scanner.nextInt(); if (choice == 1) { //管理员 return new AdiminUser(name); } else { //普通用户 return new NormalUser(name); } } public static void main(String[] args) { BookList bookList = new BookList(); //user指向哪个对象，就看返回值是什么 User user = login(); while (true) { int choice = user.menu(); System.out.println("choice:" + choice); //根据choice决定调用的是哪个方法 user.doOperation(choice, bookList); } } }
